In this April 3, 2012, file photo, connecticut religious leaders who oppose the death penalty stop for a prayer during a march to the state Capitol for a rally in favor of repealing the punishment at state level in Hartford, Conn., Tuesday, April 3, 2012. The state Senate voted Thursday, April 5, 2012, to abolish the death penalty. The bill, which has the support of the state's Democratic governor, next goes to the Democrat-controlled House of Representatives, where it's expected to win approval.

After executing just one prisoner in more than 50 years, Connecticut moved Thursday to become the 17th state without a death penalty.

But the repeal wouldn't be a lifeline for the state's 11 Death Row inmates, including two men who killed a woman and two children in a horrifying home invasion supporters touted as a key reason to keep the law on the books. The state Senate debated for hours Thursday about whether the law would reverse those sentences before voting 20-16 to repeal the law.

After the state Senate's 20-16 Thursday vote to repeal the law, the heavily Democratic state House of Representatives is expected to follow with approval within weeks. Gov. Dannel Malloy, the first Democratic governor elected in two decades, has pledged to sign the bill.

The wealthy, liberal state is one of the last in the Northeast to have a death penalty law and would join New Mexico, Illinois, New Jersey and New York as the most recent to outlaw capital punishment, states that rarely carried out the penalty before repeal. Proposals for repeal are also pending in several other states, including Kansas and Kentucky, while an initiative to end the death penalty goes before California voters in November.

Executions in the United States have declined from a high of 98 in 1999 to 43 last year, said Richard Dieter, executive director of the Death Penalty Information Center. The number of people sentenced to death each year has also dropped sharply, from 300 a decade ago to 78 last year, he said.

Dieter, a leading death penalty opponent, attributed the states' decision to repeal to "the revelation of so many mistakes," wrongful convictions exposed by new DNA evidence. A Connecticut state Innocence Project that began reviewing cases in 2005 with new DNA technology has yielded several high-profile exonerations.

One Connecticut state senator said the possibility that an innocent person could face execution weighed heavily on her conscience.

"I cannot stand the thought of being responsible for somebody being falsely accused and facing the death penalty," said Sen. Edith Prague, D-Columbia.

Connecticut has carried out only one execution in 51 years, when serial killer Michael Ross was administered lethal injection in 2005 after giving up his appeal rights.

Preserving the sentence of those still on Death Row is fairly unusual, although a similar law took effect in New Mexico.